Ship and Method for Conveying and Setting Up Offshore Structures

ABSTRACT

A ship according to the invention for conveying and setting up offshore structures having:
         a hull with a U-shaped cross-section having an open stern and projections of the side walls extending at the rear beyond the rear edge of the floor,   jack-up leg systems with jack-up legs integrated in the hull that are movable in a vertical direction with their bottom ends in positions below the floor, and   a crane that can move on the top edges of the side walls.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable.

BACKGROUND OF THE INVENTION

The invention relates to a ship and a method for conveying and setting up offshore structures. The ship and the method are especially intended for conveying and setting up offshore wind turbines.

Operating wind turbines on the sea promises a high energy yield due to high average wind speed. Consequently, more offshore wind turbines should be set up. In the North Sea, several large areas have been designated for setting up wind turbines. These are generally located outside of the 12-mile zone. The depth of water is 10 meters to a few multiples of 10. It frequently ranges from 40 to 50 m.

When setting up the offshore wind farm Alpha-Ventus, wind turbines were set up using the Thialf platform by the Dutch company Heerema. This is a very large piece of equipment that is typically used to set up oil platforms. The piece of equipment remains at the setup site for long periods. However, it only takes one to two days to set up an offshore wind turbine, and then the platform needs to be towed to another setup site. It is too time-consuming and expensive to use this piece of equipment to set up wind turbines.

WO 2004/087494 A2, the entire contents of which is incorporated herein by reference, describes a ship for transporting multiple complete wind turbines which are aligned vertically. The ship has means for transporting the wind turbines from a hold to an unloading position. In addition, the ship has winches with at least three lines with fasteners to fasten to at least three lifting points on the foundation of the wind turbine. The lines are arranged at the unloading position such that their sections running to the lifting points on the foundation are horizontally spaced from each other. The ship has arms projecting at the stern on which the winches are placed. By means of the lines guided through the winches, the wind turbines can be lowered with their foundations. The wind turbines are transported from their position in the hold on rails to the unloading position. A disadvantage with this special ship is that the wind turbines need to be transported ready assembled on their foundation so that the cargo projects high above the ship. The stability of the ship is increasingly impaired as the height or respectively number of wind turbines positioned on the ship increases. This limits the transportation capacity and possible uses of the ship.

WO 2007/091042 A1, the entire contents of which is incorporated herein by reference, describes a method and a system for transporting offshore structures as well as wind turbines. These have a support frame into which the wind turbine can be inserted on land in an upright position. The support frame is used to lift the wind turbine onto a transport ship on which it is held in an upright arrangement. The transport ship has pivoting crane arms from which the transport frame is suspended. The wind turbine is transferred from a dock to the transport ship by swinging the crane arms. At the setup site, the wind turbine is placed on a prepared foundation by swinging the crane arms in the opposite direction. The foundation has a frame that interacts with the support frame. The support frame is equipped with a plurality of legs having hydraulically controlled feet. The frame on a foundation has a corresponding number of support structures on which the feet finally rest. The feet are movable along a vertical axis depending on a hydraulic control and form a damping arrangement for installing the wind turbine on the foundation. The ship is only suitable for transporting the mast of a single wind turbine. The foundations need to be set separately. After installation, the transport ship must be sailed to a harbor to pick up another wind turbine. This is problematic when numerous wind turbines need to be set up as is the case with wind farms.

With the familiar transport ships, setting up offshore structures is strongly hindered by the influence of the swell, current and wind.

Against this background, the invention is based on the object of providing a ship and a method for conveying and setting up offshore structures that can be used independent of the swell and weather conditions, and by means of which a large number of offshore structures can be conveyed and set up within a specific time.

BRIEF SUMMARY OF THE INVENTION

The ship according to the invention for conveying and setting up offshore structures has:

-   -   a hull with a U-shaped cross-section having an open stern and         projections of the side walls extending at the rear beyond the         rear edge of the floor,     -   jack-up leg systems with jack-up legs integrated in the hull         that are movable in a vertical direction with their bottom ends         in positions below the ship's bottom, and     -   a crane that can be moved on the top edge of at least one side         wall.

The U-shaped cross-section of the hull is particularly advantageous for the strength of the ship. The ship is therefore particularly suitable for conveying heavy offshore structures. An additional advantage for the hydrodynamics of the ship and the connection of the two structures is that the jack-up leg systems can be integrated in the side walls. When setting up offshore structures, the ship can be fixed to the ocean floor by lowering the jack-up legs. The ship is thereby held in a stable reference position that is independent of the swell and influences of the current and wind. This is advantageous for setting up wind turbines because the masts must be aligned precisely vertical. In addition, the U-cross section has the advantage that the top edges of the side walls can be used as a base for the movable crane. Consequently, the crane can move above the offshore structures with which the ship is loaded. The ship preferably has a loading deck on the top side of the floor to provide a high hold over which the crane can move. By means of the movable crane, offshore structures stored on the loading deck can be picked up and transported to the projections. Between the projections, the offshore structures can be lowered and placed on the ocean floor since the hull does not have a loading deck or respectively floor there. A plurality of offshore structures placed in a row in the longitudinal direction of the hull can be brought to the setup site in a single trip and set up sequentially. The ship is therefore particularly economical to use. The crane can transport the offshore structures vertically aligned because the load lifting system of the crane can grasp the offshore structures at a high attachment point. In particular, the ship can transport and assemble masts and vertically aligned foundations of wind turbines. The wind turbine does not have to be transported and set down as a unit with the mast mounted on the foundation. The cargo therefore does not extend as high from the hull of the ship as is the case in WO 2004/087494 A2, the entire contents of which is incorporated herein by reference; consequently, the ship has more options for use.

The crane can preferably move along a rail system arranged on the top edge of at least one side wall.

According to one embodiment, the crane has a crane bridge that is supported on both side walls. The loads are thereby optimally transferred into the hull of the ship. The invention includes embodiments in which the crane is movably arranged on the top edge of only one side wall. In addition, the invention includes embodiments in which cranes that are separate from each other can move on the top edge of both side walls.

According to another embodiment, the crane is a portal crane that bears the crane bridge on supports movable on the top edges of the side walls. With the portal crane, the crane bridge is arranged particularly tall so that the ship can be used to convey and set up particularly tall offshore structures. According to another embodiment, the crane is a gantry screen. The crane bridge of the gantry crane can be directly supported and moved on the top edges of the side walls. According to another embodiment, the crane bridge of the gantry crane is movable on rails that are supported by supports on the top edges of the side walls. With this ship, the crane bridge is arranged particularly tall so that it can convey and to set up particularly tall offshore structures.

According to one embodiment, the side walls are cut out at the bottom in the area of the projections so that the bottom edge of the overhangs is arranged above the water line of the hull while sailing. The stern of the ship is therefore designed like a bracket so that the ship can sail with the hull above a pier, and a transfer site for the offshore structures is arranged between the projections. Offshore structures placed on the transfer site can be picked up with the assistance of the crane arranged on the ship and set down on the ship. The ship can therefore pick up offshore structures in a harbor without using harbor cranes. Cargo in a harbor can therefore be picked up without using the jack-up legs. The ship is preferably fixed to the floor of the harbor when loading by lowering the jack-up legs.

According to one embodiment, the ship is a semi-submersible with ballast tanks integrated in the hull and pumps to fill the ballast tanks with ballast water and/or pump out the ballast water from the ballast tanks. The ship can be sailed with empty ballast tanks to the setup site. At the setup site, the ballast tanks can be flooded so that the ship is immersed lower and more stably in the water. In this embodiment, the position of the ship is additionally stabilized by the ballast. When designed as a semi-submersible, the ship can also be used for other transportation purposes in which cargo has to be loaded and/or unloaded through the stern. For example, the ship can be used to transport pontoons or other floating cargo that can be floated into and out of the open stern.

The ship preferably has at least three jack-up leg systems for fixation in a stable position. According to one embodiment, the ship has three jack-up leg systems, wherein one jack-up leg system is integrated at the midaxis in the front of the hull, and the two other jack-up leg systems are integrated in the rear of the hull in the two side walls.

According to another embodiment, the ship has four jack-up leg systems wherein two jack-up leg systems are integrated in the sidewalls in the front of the hull opposite each other, and the two other jack-up leg systems are integrated in the rear of the hull opposite each other in sidewalls. In this embodiment, the dimensions of the jack-up leg systems do not have to be as generous as is the case with the embodiment with three jack-up leg systems in which the front jack-up leg systems is exposed to greater loads than the two rear jack-up leg systems.

The bow of the ship can be designed in a conventional manner with or without a bow nose. According to another embodiment, the ship as a deckhouse arranged at the front on the hull. The deckhouse arranged at the front on the hull does not restrict the hold.

It is to be understood that the ship has a propulsion system. This can be designed in various ways. According to one embodiment, the ship has a marine propeller drive and front and rear maneuvering aids. The marine propeller drive in connection with the bow thrusters enables the ship to be precisely positioned at the setup site and in the harbor before it is fixed with the jack-up legs. Alternately, the ship's propulsion system can comprise rudder propellers by means of which the ship can be precisely maneuvered.

According to another embodiment, the ship has a dynamic positioning system. By means of the dynamic positioning system, the ship can be automatically positioned at the setup site before it is fixed with the jack-up legs to the ocean floor.

According to another embodiment, the ship has equipment for fixing foundations and/or masts of vertically aligned wind turbines to the hull. In another embodiment, the fixing equipment comprises seats in the top side of the hull in which the foundations and/or masts can be inserted. The seats can have a circle of holes to fix masts on which the mast can be placed with a threaded ring having a complementary circle of holes. By inserting screw fittings into the circle of holes, the mast can be screwed to the hull. According to one embodiment, the seats are accessible by a gangway in the hull so that the screw fittings can be affixed and released if the threaded ring is arranged inside the mast.

According to another embodiment, the hull has fastening devices for lashing systems. These can in particular be tension cables and/or rods with fasteners on their ends and clamping devices if necessary.

The ship can be equipped with offshore structures in various ways. According to one embodiment, the ship is either equipped homogeneously with a plurality of foundations or masts of wind turbines sequentially arranged in the direction of the ship's longitudinal axis, or heterogeneously, with alternating masts and foundations of wind turbines. When heterogeneously equipped, a foundation is preferably arranged next to the stern of the ship since this has to be set down first, and then a mast is set on the foundation. The position of the ship does not have to be changed. It is also quite possible for the ship to be heterogeneously equipped with a group of masts followed by a group of foundations. After the foundations are set down, the masts can be attached to the set down foundations. At least one change of position is required to do this.

In the method according to the invention for conveying and setting up offshore structures on a ship,

-   -   the ship is loaded with the offshore structures,     -   the loaded ship is sailed to the setup site for the offshore         structures,     -   the ship is fixed to the ocean floor at the setup site using         jack-up legs,     -   the offshore structures are lowered with the crane between the         rear projections of the side walls at the setup site, and     -   the jack-up legs are lifted from the ocean floor.

According to one embodiment, the ship is fixed to the floor of the harbor with the jack-up legs before being loaded, and the jack-up legs are removed from the floor of the harbor after loading.

According to one embodiment, the ship is immersed more deeply when it is fixed to the floor of the ocean by flooding the ballast tanks. The floor of the ocean is thereby compressed below the jack-up legs to provide a solid base.

According to another embodiment, the ship is lifted with the jack-up legs with the hull at least partially out of the water. This increases the load on the jack-up legs and fixes the ship more securely to the ground. When the hull is lifted only partially out of the water with the jack-up legs, the buoyancy acts on the hull. This relieves the jack-up leg systems so that they do not have to be as strongly dimensioned as is the case with a ship with a hull that can be completely lifted out of the water with the jack-up leg systems.

According to one embodiment, the ship is positioned at the setup site for the offshore structures and/or at the loading site in the harbor with a dynamic positioning system until the jack-up legs are fixed.

According to another embodiment, the ship is loaded with offshore structures by moving the rear projections of the side walls of the ship over a pier so that the projections encompass a transfer site for offshore structures, and the offshore structures placed on the transfer site can be picked up with the assistance of a crane and placed on the hull.

According to another embodiment, the ship is loaded with wind turbines, and the wind turbines are placed on the transfer site.

According to another embodiment, the ship is loaded with foundations and/or masts of vertically aligned wind turbines, and the foundations and/or masts of the wind turbines are set up at the setup site.

According to another embodiment, the ship is loaded sequentially in a longitudinal direction with several foundations of wind turbines or several masts of wind turbines, or alternating masts and foundations of wind turbines, and the foundations are set up at the setup site, or the masts of the wind turbines are placed on foundations of wind turbines, or alternatingly, foundations are set up and the masts of the wind turbines are placed on them.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is described in the following in more detail based on the drawings of an exemplary embodiment. The drawings show:

FIG. 1 a-c a ship with three jack-up leg systems equipped with foundations and masts of wind turbines in a side view (FIG. 1 a), a vertical lengthwise section (FIG. 1 b) and a plan view (FIG. 1 c);

FIG. 2 a-c a ship with four jack-up leg systems equipped with foundations and masts of wind turbines in a side view (FIG. 2 a), a vertical lengthwise section (FIG. 2 b) and a plan view (FIG. 2 c);

FIG. 3 a-i the ship from FIG. 2 during the trip (FIG. 3 a) with lowered jack-up legs at the setup site (FIG. 3 b), when picking up a foundation (FIG. 3 c), when lowering the foundation (FIGS. 3 d and e), when picking up a mast (FIG. 3 f), when transporting the mast (FIG. 3 g), when positioning the mast above the foundation (FIG. 3 h), when placing the mast on the foundation (FIG. 3 i), each in a vertical lengthwise section;

FIG. 4 a vertical lengthwise section of the ship from FIG. 2 with lowered jack-up legs and a hull lifted out of the water at the setup site;

FIG. 5 a-j the ship from FIG. 2 when maneuvering to a transfer site for wind turbines on a pier (FIG. 5 a), when encompassing the transfer site between the protections (FIG. 5 b), when lowering the jack-up legs into the floor of the harbor (FIG. 5 c), when picking up the mast of a wind turbine (FIG. 5 d), when lowering the mast onto the ship (FIG. 5 e), when moving the portal crane to the transfer position (FIG. 5 f), when picking up a foundation (FIG. 5 g), when placing the foundation on the hull (FIG. 5 h), when positioning the portal crane in trip position (FIG. 5 i), when sailing from the pier with lifted jack-up legs (FIG. 5 j), each in a vertical lengthwise section;

FIG. 6 a-c the ship from FIG. 2 homogeneously equipped with foundations in a side view (FIG. 6 a), in a vertical longitudinal section (FIG. 6 b) and plan view (FIG. 6 c).

FIG. 7 a-c the ship from FIG. 2 homogeneously equipped with masts of wind turbines in a side view (FIG. 7 a), in a vertical longitudinal section (FIG. 7 b) and plan view (FIG. 7 c).

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there are described in detail herein a specific preferred embodiment of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiment illustrated

In the following explanation of different exemplary embodiments, corresponding parts are provided with the same reference signs.

According to FIG. 1 a ship 1.1 for conveying and setting up offshore structures has a hull 2 having a U-shaped cross section with a floor 3 and side walls 4.1, 4.2. At the front, the ship has a conventional bow 5. In addition, a deckhouse 6 is arranged in the front area on the ship. A helicopter landing pad 7 is optionally provided.

The floor 3 and side walls 4.1, 4.2 as well as the rear wall of the deckhouse 6 delimit a hold in the hull 2.

The side walls 4.1, 4.2 of the hull have projections 9.1, 9.2. projecting from the rear edge 8 of the floor 3. The projections 9.1, 9.2 each have a cutout 10.1, 10.2, the top edge of which is disposed above the water line 11 when the ship is sailing. The stern 12 of the ship is therefore designed in the shape of a bracket in a side view. Between the projections 8.1, 8.2, the hull 2 has a large opening 13. In addition, it is open to the rear at the stern 12.

A propulsion system (not shown) located in the hull 2 comprises a marine propeller drive and front and rear maneuvering aids (such as bow thrusters) and the associated drive motors.

On the top side of the floor 3 is a loading deck 14.

Furthermore, jack-up leg systems 15.1, 15.2, 15.3 with jack-up legs 16.1, 16.2, 16.3 are integrated in the hull 2. In the front part of the hull 2 directly following the deckhouse 6, there is a jack-up leg system 15.1 arranged centrally on the mid-axis 17. In the rear part of the hull 2, two opposing additional jack-up leg systems 15.2, 15.3 are integrated in the side walls 4.1, 4.2.

Each jack-up leg system 15.1, 15.2, 15.3 comprises a torsion box in which the jack-up legs 16.1, 16.2, 16.3 are guided. At the bottom end, the jack-up legs 16.1, 16.2, 16.3 have a stamp-shaped foot 18. The jack-up legs 16.1, 16.2, 16.3 can be moved vertically in the torsion boxes. To this end, drives are integrated in the jack-up leg systems 15.1, 15.2, 15.3 that for example comprise hydraulic cylinders or gears that engage with racks. The drives of the jack-up leg systems 15.1, 15.2, 15.3 have electric motors, for example.

On the top edges 19.1, 19.2 of the side walls 4.1, 4.2, a portal crane 20 is movably arranged on rails. The portal crane 20 has two sides supports 21.1, 21.2 that are guided on the rails at the bottom by rollers. At the top, the supports 21.1,21.2 are bridged by a crane bridge 22. Hoisting gear (not shown) with load lifting means is arranged on the crane bridge 22.

In addition, the portal crane 20 has drive means (not shown) for moving the portal crane 20 along the top edges 19.1, 19.2 of the sidewalls 4.1, 4.2. The portal crane 20 can be moved from a position shortly behind the deckhouse 6 up to the projections 9.1, 9.2 so that loads can be lowered with the hoisting gear through the opening 13 between the projections 9.1, 9.2.

In the example, the ship 1.1 is equipped with two complete wind turbines 23. The wind turbines 23 are divided into a foundation 23.1 and a mast 23.2 that bears the generator with the rotor 23.3. The foundation 23.1 and mast 23.2 can be vertically assembled in a conically designed connection area. The foundations 23.1 are designed as tripods. Each foot of the tripod is equipped with a nail 23.4 in a vertical guide sleeve that can be driven into the ocean floor. Rams are carried onboard the ship 1.1 for this purpose. These can be mounted on the top ends of the nails 23.4 and can be operated by means of flexible supply lines by a ship 1.1 power supply. This power supply can be electrical, hydraulic or pneumatic.

The masts 23.2 and foundations 23.1 are arranged sequentially in alternating sequence in the longitudinal direction of the ship 1.1, and a foundation 23.1 is positioned at the rear.

The foundations and masts 23.2 of the windmills 23 are arranged vertically on the load deck 14. In this position, they can be held or respectively secured by means of fixing devices (not shown).

The ship 1.2 in FIG. 2 differs from the one described above in that it has four jack-up leg systems 15.1, 15.2, 15.3, 15.4. In this ship 1.2, there are two front, opposing jack-up leg systems 15.1, 15.2 integrated in the side walls 4.1, 4.2. Contrastingly, there is no jack-up leg system at the mid-axis 17 of the ship 1.2. Ship 1.2 has a larger hold than ship 1.1.

According to FIG. 2, the portal crane 20 is in a position on the projections 9.1, 9.2 for picking up and depositing cargo. Ship 1.2, like ship 1.1, is loaded with wind turbines 23.

Optionally, ship 1.1 or 1.2 has a tailgate (not shown) at the stern 12 that can be closed during the trip in order to prevent waves from entering. The tailgate is preferably arranged at the back end of the hold or respectively at the rear edge 8 of the floor 3, and preferably extends up to the top edge of the side walls 4.1, 4.2.

In FIG. 3 a, the ship is shown as it arrives at the setup site where it is kept in this position by means of a dynamic positioning system.

According to FIG. 3 b, the jack-up legs 16.1, 16.2, 16.3, 16.4 are lowered at the setup site so that the feet 18 penetrate the sludge line 24.1 and rest on solid ground 24.2. The ship 1.2 is only lifted slightly by the jack-up legs 16.1, 16.2, 16.3, 16.4 so that the buoyancy acting on the hull 2 relieves the jack-up leg systems 15.1, 15.2, 15.3, 15.4.

According to FIG. 3 c, the portal crane 20 is moved over the rear foundation 23.1 so that it can pick it up with the load lifting means (not shown). According to FIG. 3 d, the portal crane 20 lowers the foundation 23.1 between the projections 9.1, 9.2 through the opening 13. According to FIG. 3 c, the foundation 23.1 sits on the ocean floor 24 so that the nails 22.4 can be driven in. In this position, the connecting section of the foundation 23.1 extends above the water line 11.

Then the portal crane 20 according to FIG. 3 e moves to the rear mast 23.2 and picks it up with the load lifting means.

FIGS. 3 g and h show the ship 1.2 while the mast 23.2 is being transported to the foundation 23.1.

According to FIG. 3 i, the mast 23.2 is joined to the foundation 23.1 at the conical connecting sections. Because the ship 1.2 is supported by the jack-up legs 16.1, 16.2, 16.3, 16.4, the foundation 23.1 can be vertically aligned very precisely and easily joined to the mast 23.2.

Then the jack-up legs 16.1, 16.2, 16.3, 16.4 are lifted, and the ship 1.2 is maneuvered to another set up site where the parts 23.1, 23.2 of the other windmill 23 are set up.

According to another embodiment illustrated in FIG. 4, the ship 1.2 can be lifted by means of the jack-up legs 16.1, 16.2, 16.3, 16.4 so that the hull 2 is disposed above the water line 11. The advantage is that the load from the swells on the hull and the jack-up leg system is substantially reduced.

FIG. 5 shows the ship 1.2 when loading wind turbines 23. The stern 12 of the ship 1.2 is moved to a pier 25 in the harbor. This is shown in FIG. 5 a. According to FIG. 5 b, the ship 1.2 is maneuvered so that it encompasses a loading position 26 for wind turbines 23 between the projections 9.1, 9.2 on which a mast 23.1 is waiting. In this position, the ship 1.2 is held by the dynamic positioning system. The jack-up legs 16.1, 16.2, 16.3, 16.4 are lowered so that the feet 18 penetrate the floor 27 of the harbor, and the ship 1.2 is fixed in the loading position as shown in FIG. 5 c.

Then according to FIG. 5 d, the portal crane 20 is moved to the projections 9.1, 9.2 until it overlaps with the mast 23.2. The load lifting means are fastened to the mast 23.2, and the mast is transported by means of the portal crane 20 into the position in FIG. 5 e. In this position, it is held and secured to the hull 2 by means of suitable fixing devices.

Then the portal crane 20 is moved to the rear as shown in FIG. 5 f. A foundation 23.1 is already ready between the projections. The portal crane 20 moves toward the projections 9.1, 9.2 into the position shown in FIG. 5 g. The load lifting means pick up the foundation 23.1, and the portal crane 20 lifts it into the position in the hold shown in FIG. 5 h. In this drawing, another mast 23.2 is already shown that is placed on the transfer site 26. In the above-described manner, the portal crane 20 lifts the other mast 23.2 and another foundation 23.1 until the ship 1.2 is completely equipped with two wind turbines 23 as shown in FIG. 5 i. Then, according to FIG. 5 j, the jack-up legs 16.1, 16.2, 16.3, 16.4 are lifted, and the ship 1.2 is sailed to the setup site.

FIG. 6 shows an alternative equipping of the ship 1.2 with exclusively five foundations 23.1. This equipping can be preferable to equipping with complete wind turbines 23 consisting of foundations 23.1 and masts 23.2 when for example it appears advisable to transport a load that is less tall in difficult sea and weather conditions. With a ship 1.2 equipped in such a manner, first exclusively foundations 23.2 are placed at various setup sites.

FIG. 7 shows an alternative equipping of the ship 1.2 exclusively with masts 23.2. This equipping can be preferable in good weather and favorable conditions to equip foundations 23.1 already placed at a setup site with masts 23.2.

This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto. 

1. A ship for conveying and setting up offshore structures having: a hull (2) with a U-shaped cross-section having an open stern (12) and projections (9.1, 9.2) of the side walls (4.1, 4.2) extending at the rear beyond the rear edge (8) of the floor (3), jack-up leg systems (15.1, 15.2, 15.3, 15.4) integrated in the hull (2) having jack-up legs (16.1, 16.2, 16.3, 16.4), the bottom ends (18) of which can be moved in a vertical direction into positions below the floor (2), and a crane (20) movable on the top edges (19.1, 19.2) of the side walls (4.1, 4.2).
 2. The ship according to claim 1, wherein the crane (20) has a crane bridge (22).
 3. The ship according to claim 2, wherein the crane is a portal crane (20) that bears the crane bridge (22) on supports (21.1, 21.2) that are movable on the top edges (19.1, 19.2) of the side walls (4.1, 4.2).
 4. The ship according to claim 1, wherein the side walls (4.1, 4.2) are cut out in the area of the projections (9.1, 9.2) on the bottom so that the bottom edge of the projections is disposed above the water line (11) of the hull (2) during the trip.
 5. The ship according to claim 1 that, as a semi-submersible, is provided with ballast tanks integrated in the hull (2) and pumps to fill the ballast tanks with ballast water and/or pump out the ballast water from the ballast tanks.
 6. The ship according to claim 1, having three jack-up leg systems (15.1, 15.2, 15.3), wherein a jack-up leg system (15.1) on the mid-axis (17) is integrated in the front hull (2), and two additional jack-up leg systems (15.2, 15.3) are integrated in the rear hull (2) in the two sidewalls (4.1, 4.2).
 7. The ship according to claim 1 having four jack-up leg systems (15.1, 15.2, 15.3, 15.4), wherein two opposing jack-up leg systems (15.1, 15.2) are integrated in the front in the hull (2) in the side walls (4.1, 4.2), and two additional opposing jack-up leg systems (15.3, 15.4) are integrated in the rear (2) in the sidewalls (4.1, 4.2).
 8. The ship according to claim 1 having a deckhouse (6) arranged at the front on the hull (2).
 9. The ship according to claim 1, having a marine propeller drive and front and rear maneuvering aids.
 10. The ship according to claim 1 having a dynamic positioning system.
 11. The ship according to claim 1, having devices for fixing foundations (23.1) and/or masts (23.2) of wind turbines (23) to the hull (2) in a vertical alignment.
 12. The ship according to claim 1, having seats for foundations (23.1) and/or masts (23.2) of wind turbines (23) and/or fastening devices for lashing systems.
 13. The ship according to claim 1, equipped with several foundations (23.1) or masts (23.2) of wind turbines (23) arranged sequentially in the direction of the ship's longitudinal axis, or alternating masts (23.2) and foundations (23.1) of wind turbines (23).
 14. The ship according to claim 1 that is provided with a tailgate for closing the open stern (12).
 15. A method for conveying and setting up offshore structures with a ship according to claim 1, wherein the ship (1) is loaded with the offshore structures (23), the loaded ship (1) is sailed to the setup site for the offshore structures (23), the ship (1) is fixed to the ocean floor at the setup site using jack-up legs (16), the offshore structures (23) are lowered with the crane (20) between the rear projections (9.1, 9.2) of the side walls (4.1, 4.2) at the setup site, and the jack-up legs (16) are released from the ocean floor (24).
 16. The method according to claim 15, wherein before loading, the ship (1) is fixed to the floor (27) of the harbor by means of jack-up legs (16), and after loading, the jack-up legs (16) are released from the floor (27) of the harbor.
 17. The method according to claim 15, wherein the ship (1) is immersed more deeply when it is fixed to the floor of the ocean (24) by flooding the ballast tanks.
 18. The method according to claim 15, wherein the ship (1) is lifted at least partially out of the water with the hull (2) by means of the jack-up legs (16).
 19. The method according to claim 15, wherein the ship is positioned by means of a dynamic positioning system at the setup site for the offshore structures (23) until the jack-up legs (16) are fixed in the ocean floor (24).
 20. The method according to claim 15, wherein the ship (1) is loaded with offshore structures (23) by moving the rear projections (9.1, 9.2) of the side walls (4.1, 4.2) of the ship (1) over a pier (25) so that the projections (9.1, 9.2) encompass a transfer site (26) for offshore structures (23), and the offshore structures (23) placed on the transfer site (26) can be picked up with the assistance of a crane (20) and placed on the hull (2).
 21. The method according to claim 16, wherein the ship (1) is loaded with wind turbines (23), and the wind turbines (23) are set up at the setup site.
 22. The method according to claim 15, wherein the ship (1) is loaded with foundations (23.1) and/or masts (23.2) of vertically aligned wind turbines (23), and the foundations (23.1) and/or masts (23.2) of the wind turbines (23) are set up at the setup site.
 23. The method according to claim 22, wherein the ship (1) is loaded sequentially in a longitudinal direction with several foundations (23.1) of wind turbines (23) or several masts (23.2) of wind turbines (23), or alternating masts (23.2) and foundations (23.1) of wind turbines (23), and the foundations (23.1) are set up at the setup site, or the masts (23.2) of the wind turbines (23) are placed on foundations (23.1) of wind turbines (23), or alternatingly, foundations (23.1) are set up and the masts (23.2) are placed on them.
 24. The method according to claim 15, wherein the hold of the ship is closed by a tailgate during the trip. 